滚动轴承脂润滑的速度因素及潜力

分析了影响滚动轴承脂润滑速度因素 (dN值 )的主要因素 ,阐述了合成润滑脂在提高dN值方面的巨大潜力。合成润滑脂的优越性能可望将滚动轴承脂润滑的速度因素 (dN)值提高到 10 6mm·r/min。附表 2个 ,参考文献17篇。

影响短跑速度因素探讨

通过查询资料和在多年训练中总结,分析了影响速度的几个原因,阐述了如何克服速度障碍的几个训练方法,希望同行批评指正。

田径运动中的速度因素及其基础训练

一、速度在田径各运动项目中的作用 田径专项能力包括速度、力量、耐力、柔韧、灵敏、协调能力等。随着对人体运动潜力的进一步挖掘,速度能力显得尤为重要。除了短跑项目外,对速度能力的要求也贯穿了所有其它的田径项目。 (一)速度与中长跑项目 中长跑是三种供能方式齐备的混和代谢,随着项目距离和时间的增加而逐渐从以无氧代谢为主的混和代谢向以有氧代谢为主的混和代谢过程过渡,但其中的无氧代谢的比例却随运动成绩的提高而呈增长趋势。

论影响电力业扩报装速度的因素及解决方法

对于电力业扩报装的工作而言,其任务主要为是对电力用户进行用电传输,同时也是其电力企业供电的基本途径。根据整体来分析,对电力业扩报装的速度进行改善,可以更好的提高电力企业的服务质量,促进电力企业经济效益以及社会效益的全面提高。在本文之中主要是对影响电力企业业扩报装的速度因素和解决措施作出了全面的分析研究,并且在这个基础之上提出了下文中的一些内容,希望能够给与同行业工作的人员提供一定价值的参考。

计算机数据处理的运算速度影响因素分析

计算机技术发展至今,已经成为了多元化技术的一种统称。计算机的软件技术是目前应用最为广泛的技术,也是发展最为迅速的技术。计算机技术应用于网络、工业、医疗以及教育行业等,成为了主流的应用型技术,并且在一定程度上推动了原有行业的发展,实现不同行业的协同发展模式。但是,在最初的计算机设计中,其主要的作用就是为了进行数据计算。因此,本文主要针对计算机数据处理技术进行分析,同时分析会影响计算机数据处理运算速度的影响因素。

影响货币流通速度的微观因素考察——基于中国货币收入流通速度的计量分析

本文以我国货币的收入流通速度为考察对象，在对其加以界定的基础上进行研究。本文根据弗里德曼的货币需求函数，从微观的角度对货币收入流通速度变动的原因进行了研究，并建立了回归模型进行分析，得知造成我国货币流通速度变动的影响因素是：人均实际收入增加，存、贷款利率的变化，特则是存款利率，通货膨胀率只有发生剧烈变化时才会有影响.

高精度速度分析技术在C571地区的应用

石油勘探中深层已经成为勘探的重点,是油田增储上产的主要领域,但由于中深层地震资料波场复杂、覆盖次数和信噪比较低、有效反射较弱等原因,影响了速度分析的精度,从而影响了偏移成像的质量,制约了中深层油气资源的勘探开发。利用高精度速度分析技术,提高C571地区速度谱能量团的聚焦性,改善速度分析精度,提高资料中深层成像精度。

FDI并购与新建比较研究

本文从发达国家和发展中国家外资流入方式的不同特点入手,对FDI的两种主要方式——跨国并购和新建进行了比较研究,分析了导致发达国家和发展中国家主要外资流入方式不同的原因。最后,文章结合中国的具体情况,提出了调整我国现行外资政策的建议。

中国经济发展影响农村贫困的实证分析

改革开放以来,中国经济发展极大地影响了农村贫困。以经济增长、农业发展和外贸扩大作为速度因素,以农业结构变化、非农就业发展、城乡居民比例变动和所有制结构变迁作为结构因素,以收入差距扩大和通货膨胀作为质量因素,撇开观念和制度变迁,运用SURE和SYSTEM GMM法,对中国经济发展影响农村贫困的因素分析表明,经济快速增长是推动农村贫困减少的主要动力,收入差距扩大则弱化了经济增长的减贫效应,同时农业、非农就业以及非国有企业的发展也对农村贫困减少起着明显的促进作用。

冷冻干燥速率强化技术

从冷冻干燥过程内部速率控制影响因素出发 ,阐明了冷冻干燥速率强化技术的现状和发展 。

Speed,Speed Factor and Power Input of Different Designs of Diffusion Pumps,and Remarks on Measurements of Speed

编者按:国际公认并广泛使用的何氏系数是真空术语中以中国人姓氏命名的系数.何增禄先生(1898--1979-05-12)是我国著名的物理学家、教育家、清华大学著名教授(见<真空>杂志1979年第三期第一页前).下面转载的论文是何增禄先生1932年在美国工作时发表的论文(Physics Volume 2 P386～395 may 1932).这篇在国际上很有影响、曾被很多国家用多种文字转载过的学术论文,我国65岁以下的科技工作者中极少有人读过原文.为纪念何增禄先生并配合发表评述文章,特全文转载,以供读者学习.

教你最基础的电脑知识 了解光驱之三 光驱选购

选择光驱,不能像挑选CPU那样仅仅考虑速度因素。对于光驱而盲,容错性显得更为重要。因此,在选购光驱的时候,应着重考虑这两方面的因素。一、光驱的速度与容错 1、光驱的速度笔者在上面曾说过,眼下CD-ROM速度的提升非常快,去年24倍速还是主流。

Using Path Analysis to Identify the Influence of Climatic Factors on Spring Peak Flow Dominated by Snowmelt in an Alpine Watershed

Spring snowmelt peak flow （SSPF） can cause serious damage. Precipitation as rainfall directly contributes to the SSPF and influences the characteristics of the SSPF, while temperature indirectly impacts the SSPF by shaping snowmelt rate and determining the soil frozen state which partitions snowmelt water into surface runoff and soil infiltration water in spring. It is necessary to identify the important and significant paths of climatic factors influencing the SSPF and provide estimates of the magnitude and significance of hypothesized causal connections between climatic factors and the SSPF. This study used path analysis with a selection of five factors - the antecedent precipitation index （API）, spring precipitation （SP）, winter precipitation as snowfall （WS）, 〈0℃ temperature accumulation in winter （[ATNI）, and average 〉0℃temperature accumulation in spring （AT） - to analyze their influences on the SSPF in the Kaidu River in Xinjiang, China. The results show that {ATN}, AT and WS have a significant correlation with the SSPF, while API and SP do not show a significant correlation. AT and WS directly influence the SSPF, while as the influence of[ATN] on SSPF is indirect through WS and AT. The indirect influence of [ATN[ on SSPF through WS accounts for 69% of the total influence of [ATN] on SSPF. Compared to the multiple linear regression method, path analysis provides additional valuable information, including influencing paths from independent variables to the dependent variable as well as direct and indirect impacts of external variables on the internal variable. This information can help improve the description of snow melt and spring runoff in hydrologic models as well as the planning and management of water resources.

Experimental study on dynamic elastic parameters of coal samples

Dynamic elastic parameters of coal are closely linked to crack characteristics and are lithology indicators in seismic exploration. This experimental study measured ultrasonic wave velocity of coal samples considering both parallel(90°) and perpendicular(0°) to bedding planes, and then calculated the dynamic elastic parameters(Edand ld) and their anisotropy values(AEdand Ald). The variations of Edand ld,as well as AEdand Aldwere analyzed under various confining stresses. The results show that: Firstly, a critical confining pressure exists, and significant variation in the parameters can be seen below this point and weak variation appears above it. Secondly, a positive correlation exists between Edand the square of P-wave velocity(VP2), and between AEdand the P-wave velocity anisotropy(AEP) as well; however, there is no clear correlation between ldand P-wave velocity(VP). Thirdly, according to the major controlling factors of anisotropy, the coal samples with different Edand ldas well as AEdand Aldcan be divided into two types: one is mainly controlled by bedding and cracks and the other one is mainly controlled by differences of mineral compositions in directions. Consequently, this study can provide theoretical basis for future research on the dynamic elastic parameters and anisotropy of coal.

Ultrasonic plastification speed of polymer and its influencing factors

The melt filling difficulty in micro cavity is one of the main challenges for micro-injection molding (MIM). An approach employing ultrasound in MIM was proposed. The approach was extensively studied through experiments with a home-made experimental ultrasonic plastification device. The results of the experiments show that polymer ultrasonic plastification speed increases with ultrasonic supply voltage and plastification pressure. When the ultrasonic supply voltage is 200 V and the plastification pressure is 2.0 MPa, the polymer ultrasonic plastification speed reaches the maximum value of 0.111 1 g/s. The results also indicate that the ultrasonic cavitation effect is the most significant effect of all the three effects during polymer ultrasonic plastification process.

Sap Flow of Abies georgei var. smithii and Its Relationship with the Environment Factors in the Tibetan Subalpine Region, China

Abies georgei var. smithii is a dominant species playing an important role in protecting biodiversity and sustaining the forestry ecosystems in Southeastern Tibetan Plateau. Stem sap flows of five different diameters at the breast height(DBH) A. georgei var. smithii samples were monitored continuously with the thermal dissipation probe for the entire growing period in order to understand the water transportation mechanism and the effects of environmental factors on its transpiration and growth. Relative environment factors, temperature and humidity of air, photosynthetically active radiation, rainfall, and wind speed, soil moisture, etc. were measured by the automatic weather stations. Diurnal and seasonal variations in sap flow rate with the different stem diameters and their correlations with meteorological factors were analyzed. The diurnal change in sap flow velocity showed a single-peak curve at the daily time scale, whereas a lower sap flow velocity can be observed in the largest DBH sample tree at night. The maximum average velocity was observed in August, whereas the minimum velocity was observed in January, and a large amount of water evaporated in summer owing to the higher sap flow velocity. In addition, sap flow velocity was closely related to changes in the micrometeorological factors, with average sap flow velocity showing significant linear correlations with air temperature, photosynthetically active radiation, rainfall, and vapor pressure deficit of air and soil moisture. Therefore, some measures, improving the light and temperature conditions, should be taken for protecting A. georgei var. smithii population in the Tibetan Plateau.

Sensitivity analysis on parameter changes in underground mine ventilation systems

A more efficient mine ventilation system, the ventilation-on-demand （VOD） system, has been proposed and tested in Canadian mines recently. In order to supply the required air volumes to the production areas of a mine, operators need to know the cause and effect of any changes requested from the VOD system. The sensitivity analysis is developed through generating a cause and effect matrix of sensitivity factors on given parameter changes in a ventilation system. This new utility, which was incorporated in the 3D-CANVENT mine ventilation simulator, is able to predict the airflow distributions in a ventilation network when underground conditions and ventilation controls are changed. For a primary ventilation system, the software can determine the optimal operating speed of the main fans to satisfy the airflow requirements in underground workings without necessarily using booster fans and regulators locally. An optimized fan operating speed time-table would assure variable demand-based fresh air delivery to the production areas effectively, while generating significant savings in energy consumption and operating cost.

Factors Influencing Droplet Size of Silicone Oil Emulsion with High Solid Content

A silicone oil emulsion with 60% of solid content was prepared with methyl silicone oil used as the main material by means of the emulsifier-in-oil method.The influence of emulsification conditions on the droplet diameter of silicone oil emulsion was discussed.The experimental results showed that the emulsification method,including the quantity of the emulsifier,the time and temperature of emulsification,the emulsifying water dosage,and the stirring speed,had significant impact on the droplet size.The optimal conditions were identified to achieve a smallest droplet diameter of the emulsion at an emulsifier dosage of 6%,an emulsification temperature of 70 ℃,an emulsification time of 30 min,and a stirring speed of 1100 r/min,with water added in two portions at a ratio of 1:1.The high-solid content silicone oil emulsion with a mean droplet diameter of 2.731 μm was prepared under these conditions that could ensure absence of stratification and floating oil under centrifuging at a speed of 3000 r/min for 30 min.

Clinical course of sub-centimeter-sized nodules detected during surveillance for hepatocellular carcinoma

AIM: To evaluate the outcome of sub-centimeter-sized nodules (SCSNs) detected during surveillance for hepatocellular carcinoma (HCC) in patients at risk. METHODS: We retrospectively analyzed a total of 142 patients with liver cirrhosis or chronic hepatitis B or C without a prior history of HCC in whom a SCSN was detected during HCC surveillance. We calculated the rate of HCC development from SCSNs in the study population and analyzed the differences in the baseline clinical characteristics and imaging features between the patients with SCSNs that eventually developed into HCC and patients with SCSNs that did not develop into HCC.RESULTS: During 667 person-years of follow-up, HCC developed in 33 patients. The calculated HCC development rate was 4.9% per year. The cumulative one-, two-, three- and five-year HCC development rates were 5.6%, 10.6%, 14.1% and 20.4%, respectively. Upon baseline comparison, the HCC group was older (54.4 ± 8.3 years vs 48.9 ± 9.4 years; P = 0.003) and had lower albumin levels (3.56 ± 0.58 g/dL vs 3.84 ± 0.55 g/dL; P = 0.012) and higher baseline alpha-fetoprotein (AFP) levels (8.5 ng/mL vs 5.4 ng/mL; P = 0.035) compared to the non-HCC group. Nodule pattern and initial radiologic diagnosis also differed between the two groups. Multivariate analysis revealed that age [P = 0.012, odds ratio (OR) =1.075, 95% confidence interval (CI) =1.016-1.137], sex (P = 0.009, OR = 3.969, 95% CI: 1.403-11.226), and baseline AFP level (P = 0.024, OR = 1.039, 95% CI: 1.005-1.073) were independent risk factors for developing HCC. CONCLUSION: The overall risk of HCC development in patients with SCSNs is similar to that in liver cirrhosis patients. Patients with these risk factors need to be closely monitored during follow-up.

The relationship between steeplechase hurdle economy, mechanics, and performance

Background： Research surrounding the steeplechase is scarce, with most research focusing primarily on how biomechanical factors relate to maintaining running speed while crossing barriers. One area that has not been well explored is the relationship between biomechanical factors and hurdling economy. The purpose of this study was to investigate how pel：formance times and biomechanical variables relate to hurdling economy during the steeplechase. Methods： This was accomplished by measuring running economy of collegiate and professional steeplechasers while rmming with and without hurdles. Biomechanical measures of approach velocity, takeoff distance, clearance height, and lead knee extension while hurdling, as well as steeplechase performance times were correlated to a ratio of running economy with and without hurdles. Results： While oxygen uptake was 2.6% greater for the laps requiring five barriers, there was no correlation between steeplechase performance time and the ratio of running economy during the hurdle and non-hurdle laps. Results also indicated no correlation between the aforementioned biomechanical variables and ratio of running economy during the hurdle and non-hurdle laps. Conclusion： Increasing approach velocity did not negatively affect running economy. Increased approach velocity is a benefit for maintenance of race pace, but does not hurt economy of movement.